<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
#d1{
  width: 100px;
  height: 100px;
  border: 10px solid red;
  /*圆角：值越大越圆，超过宽高一半为正圆（前提是正方形）*/
  border-radius: 60px;

}
#d2{
  width: 50px;
  height: 50px;
  border: 1px solid red ;
  /*内边距会影响元素宽高*/
  padding-left: 150px;
    padding-top: 50px;
}
  </style>
</head>
<body>
<div id="d2">内边距</div>
<div id="d1"></div>
</body>
</html>